Patent Document 1 discloses a method of forming a hard coating that enables forming a hard coating on the surface of a base substrate through deformation-induced transformation in a cold state. The method of forming the hard coating involves spraying a metal powder in a solid state onto the surface of a base substrate along with compressed gas as a medium so as to form a hard metal coating. In the forming method, the metal powder is made of a metal material that can undergo deformation-induced transformation. The method involves spraying the metal powder onto the base substrate at such a high speed that causes deformation-induced transformation, so as to accumulate and layer the metal powder on the surface of the base substrate while plastically deforming the metal powder into a flat shape as well as to cause deformation-induced transformation of the metal powder that has been accumulated. This forming method is characterized in that the metal coating formed on the base substrate is harder than the metal powder to be sprayed onto the base substrate.